A synchronous manual transmission assembly serves to couple loose wheels of transmission stages (“gears”) of a manual transmission comprising a transmission shaft when the appropriate gear is to be selected. An example of such a synchronous assembly is shown schematically in FIG. 1.
The synchronous assembly contains a synchroniser hub 10 which is arranged on a transmission shaft for conjoint rotation therewith. Arranged on the synchroniser hub is a sliding sleeve 12 which can be displaced relative to the synchroniser hub 10 in the axial direction but is fixed for conjoint rotation therewith in the circumferential direction. For this purpose, the sliding sleeve 12 is provided with an internal toothing arrangement 14 which can be displaced axially but in the circumferential direction engages into an external toothing arrangement 16 of the synchroniser hub 10 for conjoint rotation therewith.
The synchronous assembly also includes two coupling rings 18, 20 which are each connected to a loose wheel 11 of the manual transmission for conjoint rotation therewith. Each coupling ring 18, 20 is provided on its outer circumference with a coupling toothing arrangement 22 on to which the sliding sleeve 12 with its the internal toothing arrangement 14 can be slid.
In order to select a gear of the manual transmission, the loose wheel of the transmission gearwheels which is associated with this gear is coupled to the transmission shaft for conjoint rotation therewith. For this purpose, the sliding sleeve 12 is displaced in the axial direction on the synchroniser hub 10. For this purpose, a shift fork can be used which engages into a suitable outer contour of the sliding sleeve 12. In the illustrated exemplified embodiment, the outer contour 13 is a groove.
In order to connect e.g. the gearwheel allocated to the coupling ring 18 to the transmission shaft for conjoint rotation therewith, the sliding sleeve 12 in FIG. 1 is displaced to the left until it engages with its internal toothing arrangement 14 into the coupling toothing arrangement 22. In this state, the gearwheel is connected to the transmission shaft via the coupling ring 18, the coupling toothing arrangement 22, the internal toothing arrangement 14 of the sliding sleeve 12, the external toothing arrangement 16 of the synchroniser hub 10 and finally the synchroniser hub itself.
The shifting procedure and in particular the matching of the rotational speeds of the synchroniser hub 10 and of the corresponding gearwheel (the “synchronisation”) involve a number of further components which are not necessary for understanding the invention described in this case, e.g. synchroniser rings 24 and pressure pieces 26.
It is known from the prior art to produce the sliding sleeve 12 in an individual manner in a machining method. This gives rise to comparatively high costs.
The object of the invention is to provide a sliding sleeve in a cost-effective manner without causing any losses in terms of quality.